I hiked through the rainforest a couple times while on a school trip in Costa Rica. It was absolutely amazing.
On one hiking trip we hiked to the La Fortuna waterfall. It rained the entire time and we had to wear ponchos the whole time to keep us dry, which did not work at all. The waterfall itself was gorgeous. We were given the opportunity to swim in the river that was under the waterfall which i opted out of because I was already soaked. When we got back to our charter bus, my shirt was so wet that it was see-through and i was exhausted but it was definitely worth it.